full screen #141

Pushed. Tests: 631 pass, 0 fail (bun test), and a fresh bun run build matches the committed bundles.

The stage — the box both canvases, the HUD, the touch pads and the overlays live in — now goes on the whole screen, in all three games, with the same two gestures: a button in its top corner and a key (F in the shooter and the example, G in the range, because F is the range's trigger). src/engine/fullscreen.ts is the new module behind the door and the whole of what a game needs around the Fullscreen API: supported, so a browser that will not put an element full screen — an iPhone will not — leaves the button hidden instead of shipping one that does nothing; on, read from the document every time rather than remembered, because a person leaves with Escape and no code of ours runs; enter, exit, toggle, onChange, detach; and a refusal (no gesture, a policy, a browser that throws where it should reject) swallowed rather than thrown. The shell renders #full last in the stage so it paints over the overlays, and renders it hidden because it is the one control on the page that does nothing without a script — each entry reveals it once it has asked its browser — and the style block puts back every rule that sized the stage (the 16:9 box, the phone's 4:3, the 78vh cap, the border) when the stage is the screen.

Worth a look in the preview: press F on /, G on /range, F on /example, and the button on each — the label, the title and aria-pressed follow the state, including when you leave with Escape. On a phone the button is the only way in and it is the 44px target every other control here is. What I did not do: Play does not put you full screen by itself, because a click that takes over the screen without being asked is worse than a key; and if your browser hands the pointer back on the switch mid-match, the existing pause screen appears and Resume takes it again — that path is unchanged. The range's and the example's size ceilings are raised to today's size plus about 10%, the way every other number in src/games.ts was set, and the reason is written beside them: this is the first module behind the door that is code a browser actually runs, so all three bundles grew about a kilobyte (app 73,130 raw / 33,948 gzipped, range 29,975 / 12,704, example 9,735 / 4,620). No dependency was added. The app's terminal is unchanged: full screen is a browser affordance and there is nothing on / it makes reachable that src/tty.ts does not already show.

🤖 Generated with Claude Code

Closes #132